Endometrial Cancer Biomarkers
What Patients Need to Know
Molecular classification of endometrial cancer now places tumors into four groups — based on PTEN, MSI-H/dMMR, and POLE status — and each group calls for a different treatment approach.
Reviewed by XpertPatient Medical Advisory · Updated June 2026 · Sources: NCI · ACS · ASCO · NIH/PMC
Why This Matters
How molecular testing guides uterine cancer treatment
Doctors now classify endometrial (uterine) cancer into four molecular groups based on biomarker testing. Each group behaves differently — and each has its own best treatment approach.
This isn’t just background information. Your molecular group can change how much treatment you need — some patients may need less, and some may be eligible for immunotherapy.
The Biomarkers Your Doctor Tests
🔍 Is a key tumor-blocking gene missing?
PTEN is a gene that normally stops cancer from growing. It’s lost in up to 80% of endometrial cancers. PTEN loss activates a growth pathway called PI3K — a target being studied in new drugs.
🔍 Does your cancer respond to immunotherapy?
About 25% of endometrial cancers are MSI-H. These tumors respond well to pembrolizumab immunotherapy, which is now FDA-approved for dMMR endometrial cancer. This is one of the most important tests to have done.
🔍 Is there a mutation in a cancer growth pathway?
PIK3CA mutations are found alongside PTEN loss in many endometrial cancers. They’re being studied as targets for a new class of drugs called PI3K inhibitors.
Common Questions
Endometrial Cancer Biomarkers — Frequently Asked Questions
❓ What are the four molecular subtypes of endometrial cancer?
The four groups are: (1) POLE-mutated — best outcomes, may need less adjuvant treatment; (2) MSI-H/dMMR — responds well to immunotherapy; (3) NSMP (no specific molecular profile) — intermediate risk; (4) p53-mutated — most aggressive, needs intensive treatment.
❓ What does MSI-H mean for my treatment?
MSI-H endometrial cancer responds to PD-1 checkpoint inhibitors like pembrolizumab. It’s now FDA-approved for dMMR endometrial cancer that has progressed after chemotherapy, and it’s being studied as a first-line treatment as well.
❓ Do I need molecular testing for early-stage endometrial cancer?
Yes. Even for early-stage disease, molecular classification now guides decisions about adjuvant radiation and chemotherapy. A POLE mutation (the best subtype) may mean you need less treatment; a p53 mutation may mean you need more.
❓ What is a POLE mutation and why is it good news?
POLE is a gene involved in DNA copying. When it’s mutated in a specific way (ultramutated), it actually creates a lot of errors that make the cancer very visible to the immune system — leading to excellent outcomes. POLE-mutated endometrial cancer has the best prognosis of all four subtypes.
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Visit the Endometrial Cancer Center → Full Biomarkers Guide →
